It's a bit hard to answer because there are probably hundreds of reconditioned computers for sale on Ebay from different people, I'm sure some are fully legal and some aren't.
Ask if it has the windows COA sticker on it, if it does than you have the license to use windows on it.
As to where they get them from, could be trade ins on new computers, from companies that have upgraded...... all sorts, why not ask the seller.



